Enzyme modification of cheeses provides cheeses or cheese products with altered physical properties, such as melting and texture, and enhanced flavors. In general, enzyme modification may be carried out with hydrolytic enzymes that convert many of the components present in cheese. Most commonly, the enzymes used are lipases and/or proteases.
Many processes are known that employ both lipases and proteases. When applied to an already-prepared cheese curd, the product acquires new or enhanced flavors, and may be used either by itself or as a flavorant for other products. U.S. Pat. No. 4,595,594 discloses an intensified cheese flavor product that is prepared by incubating cheese, or cheese curd, with a lipase preferably in combination with a neutral protease. The enzyme(s) are allowed to partially digest the cheese as evidenced by a smooth, easily agitatable mixture, adding cream and incubating until the desired intensified cheese flavor is obtained. The intensity of the cheese flavor is so high that the product must be diluted prior to use. More specifically, Cheddar cheese or fresh curds are treated with the enzymes for about 48 hours.
U.S. Pat. No. 4,752,483 discloses a process for the rapid production of highly flavored cheese ingredients. A cheese curd is combined with water, protease, and lipase, and incubating for a time sufficient to produce a cheese-flavored ingredient. In particular, the process may use cheddar-type or American-type cheese curd less than about 60 days old. American-type cheese curd aged less than 60 days was reduced to particles less than about 2 millimeters. It was combined with aqueous lipase and protease and treated for 5.5 days to provide a highly flavored cheese ingredient. U.S. Pat. No. 5,211,972 discloses compositions including cheese or heavy cream in which the lipids or the proteins are enzymatically modified, and that provide a variety of desired cheese flavor profiles, without using exogenous microorganisms. Heavy cream and/or a hard, ripened cheese are treated with a lipolytic enzyme; hard, ripened cheese is treated with a proteolytic enzyme which is either an acid protease or a neutral protease. The lipolysis of the heavy cream proceeds at 38.degree. C. for 16 hours, and the proteolysis of cheddar cheese likewise proceeds at 38.degree. C. for 16 hours.
U.S. Pat. No. 5,455,051 discloses a flavorant composition having intensified blue cheese character which is obtained by treating blue cheese in an aqueous dispersion and incubated with spores of Penicillium roquefortii and with lipase and protease enzymes. The treatment proceeds long enough for the spores and the enzymes to hydrolyze and metabolize the blue cheese. In the examples, lipase and protease treatment, together with the spores, proceeds for about 24 hours.
Normally, enzyme-modified cheese flavorings are made using cheese or cheese curd as the starting material. These materials typically contain caseins as the principal protein and have low amounts of whey proteins, or none at all. It is less economical to make enzyme-modified cheese flavorings from cheese, as opposed to making them from milk or other dairy liquids. However, such dairy liquids contain whey proteins as well as, or in place of caseins. In processes in which milk or a milk product are used, they typically are subjected to a heating for pasteurization before being treated with the enzymes, in order to avoid microbial contamination during the lengthy enzyme treatment. Such heating has been found to be generally detrimental because, among other effects, it induces the whey proteins to aggregate. The aggregated whey proteins are not readily available for the action of an added protease. This difficulty is commonly overcome, when enzyme-modified cheese flavorings are prepared, by allowing incubation of the pasteurized milk or milk product for long periods (e.g., 64 hours or longer).
There remains a need, therefore, for a more efficient method of making enzyme-modified cheese flavorings that treats milk or a dairy liquid rather than treating a cheese curd or an aged, prepared cheese. There further remains a need for a method for melting enzyme-modified cheese flavorings which employs dairy liquids that include whey protein as the starting material and avoids coagulating aggregating the whey protein prior to being treated with the enzyme. In addition, there remains a need for a method of treating milk or a dairy liquid with enzyme for only a short period of time to produce an enzyme-modified cheese flavor, thereby increasing manufacturing efficiency The present invention addresses these needs.